My heart was heavy, for its trust had been
Abused, its kindness answered with foul wrong;
So, turning gloomily from my fellow-men,
One summer Sabbath day I strolled among
The green mounds of the village burial-place;
Where, pondering how all human love and hate
Find one sad level; and how, soon or late,
Wronged and wrongdoer, each with meekened face,
And cold hands folded over a still heart,
Pass the green threshold of our common grave,
Whither all footsteps tend, whence none depart,
Awed for myself, and pitying my race,
Our common sorrow, like a mighty wave,
Swept all my pride away, and trembling I forgave!

John Greenleaf Whittier

http://www.poemhunter.com/poem/forgiveness/